A: Ultraviolet Absorption 197U—

B: To a solution of 10 mg in 5 mL of water add 1 drop of ferric chloride TS: an intense green color is produced, and it becomes olive-green on standing.

C: To a solution of 10 mg in 1 mL of water add 1 drop of phosphotungstic acid TS: a white precipitate is formed immediately and it becomes brown on standing (distinction from epinephrine, which forms no precipitate).

D: Dilute 1.0 mL of a solution (1 in 1000) with water to 10 mL, add 0.1 mL of dilute hydrochloric acid (1 in 120), then add 1.0 mL of 0.10 N iodine. Allow to stand for 5 minutes, and add 2.0 mL of 0.10 N sodium thiosulfate: a salmon pink color is produced (distinction from norepinephrine, which, at the same pH, about 3, produces no color or at most only a slight pink color).

E: It responds to the tests for Sulfate 191.

(Official January 1, 2007)

Standard preparation— Prepare as directed in the Assay under Isoproterenol Hydrochloride.

Assay preparation— Transfer about 125 mg of Isoproterenol Sulfate, accurately weighed, to a 25-mL volumetric flask, dissolve in sodium bisulfite solution (3 in 1000), dilute with sodium bisulfite solution to volume, and mix. Transfer 5.0 mL of this solution to a 100-mL volumetric flask, dilute with 0.17 N acetic acid to volume, and mix.

Chromatographic system— Proceed as directed for Procedure in the Assay under Isoproterenol Hydrochloride. Calculate the quantity, in mg, of (C11H17NO3)2·H2SO4 in the portion of Isoproterenol Sulfate taken by the formula: in which 260.30 is one-half of the molecular weight of anhydrous isoproterenol sulfate, 247.72 is the molecular weight of isoproterenol hydrochloride; and C, hU, and hS are as defined therein.